1. Field of the Invention
The present invention relates to a system and method for processing signals for the real-time detection of a periodic functional activity, in particular a respiratory muscular activity.
2. Description of the Related Art
Devices are known for monitoring the respiratory activity of a patient that comprise a single sensor measuring the respiratory muscular activity. In general, this measuring sensor is an electrode placed near the explored muscle to obtain a good signal to noise ratio. According to the article “Neural control of mechanical ventilation in respiratory failure, Nature medicine 1999, Sinderby et al.”, the obtained quality of the signal allows real-time monitoring of a respiratory aid device, such as a ventilator, through the respiratory muscle activity (RMA) of a single muscle: the diaphragm. However, this solution is not suitable for measuring the activity of respiratory muscles other than the diaphragm. Furthermore, although it is not an intramuscular measurement (using a needle), this measurement is invasive.
Noninvasive devices are known that comprise a surface electrode, the measurement of which is not robust. To that end, noninvasive devices exist that comprise a surface electrode having a signal that is synchronized with a flow signal. According to the article “Optimized analysis of surface electromyograms of the scalenes during quiet breathing in humans, Respiratory Physiology & Neurobiology 2006, Hug F. et al.”, these devices make it possible to obtain, precisely and robustly, the location of the triggering of inhalation activity of the scalene muscles. However, this measurement is lengthy and assumes a certain stationarity of the respiratory activity; it is consequently not adapted to real-time detection of respiratory activity and therefore cannot be used to monitor a ventilator.